The present invention relates to a peripheral catheter assembly of the kind comprising a hollow catheter hub having a female proximal end and a distal end provided with a catheter tube, at least one infusion port located between said distal end and said proximal end, a hollow needle module comprising a needle hold by a male socket arranged to sealingly engage the female proximal end, and a sealing member engaged inside the catheter hub.
Indications for establishing intravenous access using a peripheral vein catheter can e.g. be the needs for administration of liquids, drugs or nutrients or transfusion of blood or blood products. In a peripheral vein catheter a small, flexible tube is used to deliver fluids into the body.
Conventional peripheral vein catheters, which has been used for decades, for example a Venflon™ obtainable from Becton Dickinson Infusion Therapy, Helsingborg, Sweden, comprise a hollow main body with a female end plug accommodating a needle hub with a male socket carrying a puncture needle for inserting a catheter into the vein, usually in the back of the hand or in the forearm. A common Venflon™ has an infusion port perpendicular to the main body. The infusion port is fluid sealed from the main body simply by means of a short piece of an axially compressible, hollow tube inserted inside the main body just below the infusion port. The skilled person is aware that a major disadvantage and annoyance is that the tube is hollow along the entire length, with the result that when the puncture needle is removed, blood is able to flow freely out of the open female end of the main body. The only remedy is to establish stasis to slow or stop this blood flow by compressing the penetrated vein with a finger on one hand while struggling with the other hand to quickly plug in an external device, such as e.g. a male luer connector connected to a drip. Even though, it is difficult to avoid minor blood loss and blood splashing. Moreover, during this awkward procedure the physician needs to have all remedies, including substitute remedies, within reach before puncture because he cannot leave the patient.
From US 2001/005389 is known an over-the-needle catheter comprising a hub without infusion port. The hub is permanently equipped with a sharp pointed cannula, in the same manner as a trocar. A T-shaped septum seal is mounted on the end of a metal tube, which is firmly fixed inside the hub. The T-shaped septum seal consists of a shank, i.e. a short, narrow tubular portion, and a head portion with a small central weakened portion. The T-shaped septum seal is slidably arranged on the metal tube, causing the metal tube to penetrate the weakened portion and open a permanent flow path through the bores of the cannula and the metal tube upon forward movement of the T-shaped septum seal towards the cannula. A conical male luer connector may be used for pushing the T-shaped septum seal forward to provide permanently and irreversibly penetration of the weakened portion. However, a disadvantage of this design is that if the male luer connector is disconnected the T-shaped septum seal cannot close again and the flow passage is open. Furthermore, the thin shank of the T-shaped septum seal has no sealing capacity. This shank only serves as a guide and mounting member when pushing the T-shaped septum seal along the axial length of the metal tube, and the T-shaped septum seal cannot be retracted once it has been pushed forward.
U.S. Pat. No. 5,041,097 describes an intravenous catheter with a protective end seal at the connection end for preventing fluid leakage during installation, connection, and use. A thin membrane seal formed of resilient, stretchable material is secured over the opening at the exterior surface of the rear end of the catheter base. In the assembled and packaged condition a needle with a bevelled front end is installed in the catheter. The bevelled front end of the needle is pushed through the membrane seal to puncture the membrane seal, which seal is stretched as the forward motion of the needle continues, and conforms to the profile of the needle base and allow it to engage the interior of the catheter base. When the needle is retracted, it is intended that the membrane seal revert to its start condition. A male luer connector can be installed in the base in a similar forceably manner. Both the needle base and the male luer connector must expand the small puncture hole in the stretchable membrane considerably to create sufficient bulk space for the base or connector. However, the major force which is required to allow this entails a considerable risk that the membrane seal either bursts or is pulled out of its attachment. In both cases the membrane seal is unable to close the flow path through the base again if e.g. the male luer connector is disconnected. Moreover, the elastic membrane seal is susceptible to be detached from the base when subjected to the pushing forward force. Thus, improvements in these type devices are needed.